High-temperature deformation mechanism of γ-TiAl-based alloy with ultrafine grains

ABSTRACT

Equiaxed ultrafine duplex alloys γ-TiAl and α₂-Ti₃Al are prepared by high-energy milling and hot pressing sintering. Microstructures presenting in the mixed and sintered powders are studied by scanning electron microscopy. Structural characteristics are investigated by high-resolution electron microscopy before and after compression at 1100–1200°C. The data reveal grain sizes of 300–500 and ∼100 nm for sintered γ-TiAl and α₂-Ti₃Al alloys, respectively. High deformation temperatures and low strain rates lead to low peak flow stress, and at such conditions the α_2/γ and α_2/α₂ interfaces are prone to forming dislocation structure. The studies also reveal the presence of large-angle grain boundaries for the and (0002)α₂/(0002)α₂ interfaces.

KEYWORDS:

• High-energy milling
• hot pressing sintering
• TiAl-based duplex alloy
• ultrafine equiaxed duplex alloy
• high-temperature compression

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Xuebo Gong http://orcid.org/0000-0001-6533-2768

Additional information

Funding

The authors are thankful to the National Natural Science Fund (no. 51371038) for providing financial support.